Medical device recharge systems using a controller in wireless communication with a separate recharge device

ABSTRACT

Medical device recharging systems include a controller and a separate recharge device that communicate wirelessly together to provide recharging to an implantable medical device. Either the controller or the recharge device may also communicate wirelessly with the implantable medical device to obtain recharge status and other information. There may be multiple recharge devices present within communication range of the controller, and the controller may determine which recharge device to activate depending upon proximity of each recharge device to the implantable medical device. The controller may allow the recharge device that is active at any given time to change so that the patient having the implantable medical device can move about in the area where the recharge devices are located while recharging continues.

RELATED APPLICATIONS

The present application is a divisional application of U.S. applicationSer. No. 13/016,711, filed on Jan. 28, 2011, now U.S. Pat. No.8,634,927.

TECHNICAL FIELD

Embodiments relate to medical systems that include a rechargeablemedical device. More particularly, embodiments relate to medical systemsthat include a controller that wirelessly communicates with a separaterecharge device that delivers the recharge energy to the rechargeablemedical device.

BACKGROUND

Medical systems that include medical devices having rechargeablebatteries typically utilize near field telemetry for communications witha controller. The controller may also include recharge functions so thatthe controller may utilize the same telemetry head to transfer therecharge energy to the medical device in addition to exchangingtelemetry communications.

This configuration provides a workable solution but there may bedrawbacks. In particular, a telemetry head extending from the controllermay be manually held in place relative to the medical device during therecharge process as well as during telemetry communications. A cord fromthe telemetry head to the controller may be a burden to the patient asthe cord may be an annoyance and may need to route through clothes ofthe patient to provide proper connectivity.

This configuration may provide additional drawbacks. For instance, insome cases the transfer of recharge energy may pause during near fieldtelemetry communications being used to monitor the recharge processthereby further prolonging the recharge process. As another drawback,the controller may be relatively expensive, especially considering thecontrol and recharge functions are both included, such that havingmultiple devices capable of providing the recharge function calls formultiple controllers which may be costly to the patient.

SUMMARY

Embodiments address issues such as these and others by providing medicalsystems that include a controller that is in wireless communication witha separate recharge device. Accordingly, no cords are needed between thecontroller and a recharge head. Furthermore, multiple recharge devicesmay be used with a single controller. In some cases, the controller maybe provided with wireless communication with the medical device inaddition to the wireless communication with the recharge device so thatthe recharge device does not communicate with the medical device.

Embodiments include a method of recharging an implantable medical devicethat involves initiating wireless communications between a firstcontroller and a first recharge device that provide first rechargeinstructions from the first controller to the first recharge device tocontrol recharging. The method further involves transferring rechargeenergy from the first recharge device to the implantable medical devicein accordance with the first recharge instructions.

Embodiments include a medical system that includes a first controllerhaving a wireless communication circuit. The medical system furtherincludes a first recharge device having a wireless communication circuitin wireless communication with the wireless communication circuit of thefirst controller and having a wireless recharge circuit. The firstrecharge device receives first recharge instructions from the firstcontroller and generates recharge energy in the recharge circuit basedon the first recharge instructions. The medical system further includesan implantable medical device having a wireless recharge circuit havinga wireless near field coupling to the wireless recharge circuit of thefirst recharge device to receive recharge energy from the first rechargedevice.

Embodiments include a method of recharging an implantable medical devicethat involves sensing the presence of a first recharge device. Themethod further involves, in response to sensing the presence of thefirst recharge device, instructing the first recharge device to beginthe transfer of recharge energy from the first recharge device to theimplantable medical device.

Embodiments include a medical system that includes an implantablemedical device, a first recharge device, and a controller. Thecontroller senses the presence of the first recharge device and inresponse to sensing the presence of the first recharge device, instructsthe first recharge device to begin the transfer of recharge energy fromthe first recharge device to the implantable medical device.

Embodiments include a method of recharging an implantable medicaldevice. The method involves initiating wireless communications between afirst controller and the implantable medical device that provide firstrecharge instructions from the first controller to the implantablemedical device to control recharging. The method further involvesinitiating wireless communications between the implantable medicaldevice and a recharge device to provide the first recharge instructionsfrom the implantable medical device to the first recharge device. Themethod also involves transferring recharge energy from the firstrecharge device to the implantable medical device in accordance with thefirst recharge instructions.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a medical system with recharge abilitiesaccording to various embodiments.

FIG. 2 shows an example of components of an external controller of themedical system.

FIG. 3 shows an example of components of an implantable medical deviceof the medical system.

FIG. 4 shows a first example of components of an external rechargedevice of the medical system.

FIG. 5 shows a second example of components of an external rechargedevice of the medical system.

FIG. 6 shows a first example of operations of the external controller toconduct a recharge session.

FIG. 7A shows a second example of operations of the external controllerto conduct a recharge session.

FIG. 7B shows an example of operations of the external recharge deviceto provide recharge energy during a recharge session.

FIG. 8 shows a first example of operations of the external controller toinitiate a recharge session with a particular recharge device.

FIG. 9 shows a second example of operations of the external controllerto initiate a recharge session with a particular recharge device.

DETAILED DESCRIPTION

Embodiments provide an external controller with a wireless communicationlink to an external recharge device. The external recharge deviceprovides a wireless coupling to an implantable medical device (IMD) totransfer recharge energy to the IMD. The external controller and/or theexternal recharge device may provide a wireless communication link tothe IMD. The controller and IMD may be used in conjunction with multiplerecharge devices, and the controller may initiate recharge of the IMDusing a recharge device that is in closest proximity.

FIG. 1 shows an environment that includes an external controller 102,such as a clinician programmer or a patient programmer that is nearby apatient 108 who has an IMD 104. The IMD 104 may be implanted within ormounted externally to the body 108 and may perform one or more medicaltasks such as cardiac or neurological stimulation, physiologicalsensing, drug infusion, and the like. The IMD 104 may include components106 such as stimulation or sensing leads or drug delivery catheters thatextend from the IMD 104 and terminate at the target area of the body108.

The patient 108 ultimately wants the IMD 104 to be recharged so thatmedical therapy can continue. The controller 102 may provide variousfunctions including a recharge function whereby a recharge session isestablished in order to transfer recharge energy between an externalrecharge device 111 and the IMD 104. During the recharge session,recharge energy is provided while a wireless communication session, suchas a far field communication session for example, is also conducted toallow the controller 102 to receive feedback about charging status fromthe IMD 104. The communication session with the IMD 104 may be directlywith the controller 102 or directly with the external recharge device111 if the external recharge device 111 is so equipped or with both thecontroller 102 and the recharger 111. In the two latter cases, thecontroller 102 then conducts a wireless communication session, such as afar field communication session for example, with the external rechargedevice 111 to instruct the external recharge device 111 to providerecharge energy as is appropriate and also to obtain informationregarding the recharge status that has been provided by the IMD 102.

In some embodiments, the controller 102 communicates with the IMD 104during a recharge session through a wireless communication session suchas by utilizing far field signals 114 sent by the controller 102, forexample, to obtain recharge status information from the IMD 104. Thecontroller 102 may also communicate via wireless communication signals,such as far field communication signals 114 for example, with therecharge device 111 such as to provide instructions to the rechargedevice 111 to begin transferring recharge energy, and the rechargedevice 111 may communicate acknowledgement of the instructions to thecontroller 102 via the wireless communication signals, such as far fieldcommunication signals 115 for example. The IMD 104 may communicate withthe controller 102 by sending wireless communication signals, such asfar field communication signals 116 for example.

In other embodiments, the recharge device 111 may communicate with theIMD 104 via the wireless communication signals such as the far fieldsignals 115 to obtain recharge status information from the IMD 104. Therecharge device may then communicate that information via the wirelesscommunication signals such as the far field signals 115 to thecontroller 102 rather than the controller 102 communicating directlywith the IMD 104 for the recharge status information. The IMD 104 maycommunicate with the recharge device 111 by sending the wirelesscommunication signals such as the far field signals 116 or via a nearfield communication link.

In another embodiment, the controller 102 may communicate with the IMD104 via the wireless communication signals such as far fieldcommunication signals 115 or via near field proximity signals to obtainrecharge status information from the IMD 104 and send recharge settingsfor the recharge device to the IMD 104. The recharge device 111 may thencommunicate with the IMD 104 via a wireless communication link such as anear field communication link in order to receive information aboutaltering the recharge which was stored in the IMD 104 by the controller102.

The far field signals 114, 115, and 116 that may be used in someexamples may be radio frequency (RF) signals such as those of theMedical Implant Communications Service (MICS) band that spans 402-405MHz, the Industrial, Scientific, and Medical (ISM) band, or the shortrange device (SRD) band. These far field communication signals,particularly for the communications between the controller 102 and therecharge device 111, may utilize protocols such as the Bluetooth®protocol that spans 2402-2480 MHz to exchange information. Far fieldtelemetry communications are those where a wave is propagated and thatwave may be used to carry the communications as opposed to relying on aninductive coupling. Thus, far field telemetry communications are thosewhere the signal may travel a distance in excess of one wavelength ofthe carrier frequency.

While the single IMD 104 is shown in FIG. 1, it will be appreciated thatthere may be other IMDs and/or other external devices nearby and inrange of the far field signals 114 of the external device 102 and/or thefar field signals 115 of the recharge device 111. Where the IMD 104 isbonded via a shared key or other technique to the controller 102 and/orthe recharge device 111, then the bond allows the far fieldcommunication session with the correct IMD 104 to be initiatedregardless of the presence of other IMDs. In some situations such aswhere a new controller 102 or recharge device 111 is being used tocommunicate with the IMD 104 for the first time such that no bondexists, the controller 102 and/or recharge device 111 may not be awareof identification information of the intended IMD 104 in advance suchthat the controller 102 and/or recharge device 111 cannot immediatelydiscern far field communications of the intended IMD 104 relative to farfield communications of other IMDs such that an initial proximity basedbonding process may be used. A bond may then be created between the IMD104 and the controller 102 and/or recharge device 111 by sharing anencryption key or other similar information used to establish the bond.

Physical proximity can be established to allow proximity communication112 to occur between the controller 102 and the intended IMD 104 or toallow a proximity communication 105 to occur between the recharge device111 and the intended IMD 104. Physical proximity refers to the intendedIMD 104 being positioned closely to the external device 102 to theextent that an observer such as a clinician can confirm that theintended IMD 104 is the only IMD that can be responsive to proximitycommunications. Where the proximity communication is a near field signalfrom the proximity telemetry, the proximity telemetry communications arethose where the signal may travel a distance less than one wavelength ofthe carrier frequency, which is typically an inductively coupled signaltransfer. For proximity telemetry, the external device 102 must bewithin physical proximity of the IMD (i.e., within the patient's“personal space”) for the IMD to communicate with the external device.This is opposed to far field communications wherein external device 102may, but need not, be within physical proximity of the IMD tocommunicate with the IMD.

Therefore, a procedure is provided that utilizes this physical proximityat the initiation of the far field communication session to avoid thecontroller 102 and/or recharge device 111 conducting a far fieldcommunication session with an unintended nearby IMD while the rechargedevice 111 is recharging the intended IMD 104. To allow the controller102 and/or recharge device 111 to select the intended IMD 104 for farfield communication during a recharge session and avoid selecting anunintended nearby IMD, the proximity communication signals 105 or 112may be exchanged between a proximity communicator 110 of an embodimentof the controller 102 or a proximity communicator 109 of an embodimentof the recharge device 111 and the IMD 104 during the establishment ofthe far field communication session. The proximity communicator 110and/or the proximity communicator 109 may be contained within thecontroller 102 or recharge device 111, respectively rather than beingtethered.

The proximity communicator 109 or 110 may be of various forms and may bea separate component of the recharge device 111 or controller 102 or beintegrated with the recharge device 111 or controller 102, or acombination of both. For instance, the proximity communicator 109 or 110may be a near field telemetry head that is tethered to the rechargedevice 111 by a communication path 119 or to the controller 102 by acommunication path 118. The communication path 118 or 119 may be ofvarious forms such as a cable or a wireless connection.

For embodiments of the recharge device 111, the proximity communicator109 may also integrate recharge circuitry including a recharge coil thatinductively couples to a coil of the IMD 104 to inductively transferenergy. Thus, a single tool may be placed in physical proximity of thepatient 108 in order to establish a form of proximity communication andto delivery recharge energy. The recharge energy may be sourced from anon-board power supply of the recharge device 111 where it is fed to theproximity communicator 109 for delivery to the IMD 104.

Additionally, according to some embodiments, the proximity communicator109 or other source of near field telemetry of the recharge device 111may be used to communicate with the IMD 104 via proximity signals 120rather than using far field communication signals 115 and 116. Therecharge device 111 may use the proximity signals 120 to obtain therecharge status information from the IMD 104 which can then be providedto the controller 102 via the far field communication signals 115.

In some embodiments, the controller 102 may be paired to a singlerecharge device 111. However, in other embodiments, the controller 102may be paired to multiple recharge devices 111 where multiple rechargedevices 111 may be in the general vicinity of the controller 102 and IMD104 as shown in FIG. 1. Thus, the controller 102 may communicate with afirst recharge device 111 for one recharge session and may communicatewith a second recharged device 111 for a different recharge session,where the patient is located closer to the first or second rechargedevices for any particular recharge session. Furthermore, as discussedbelow, the controller 102 may allow the patient to roam about during arecharge session whereby the controller 102 activates and deactivatesfirst and second recharge devices 111 depending upon which rechargedevice 111 is in closest proximity to the IMD 104 of the patient at anygiven time during a recharge session.

FIG. 2 shows components of one example of the controller 102. Thecontroller 102 includes a processor 202, a memory 204, and a storagedevice 206. The controller 102 may also include local input/output (I/O)ports 208 such as to provide local screen displays and to receive userinput via keyboard, mouse, and so forth. For examples wherecommunication with either the recharger 111 and/or the IMD 104 is viafar field communications, the controller 102 also includes far fieldcommunication circuitry 210 used to establish the far fieldcommunication session with the recharge device 111 and/or the IMD 104.The far field communication circuitry 210 may drive a signal propagationtool such as an RF antenna. The signal propagation tool may be includedwithin the proximity communicator 110 so that the far fieldcommunication circuitry 210 instructs the signal propagation tool overthe connection 118 or the signal propagation tool may be a separateexternal component or housed within the controller 102.

In addition to the far field communication circuitry 210, someembodiments of the controller 102 may also include a proximitycommunication circuitry 212, particularly those embodiments where thecontroller 102 communicates directly with the IMD 104 and/or recharger111 via far field communications. The proximity communication circuitry212 may be of various forms to interact with the IMD 104 via theproximity communicator 110 so as to ensure that the controller 102 iscommunicating with the intended IMD 104 via the far field communicationsignals 114, 116. The proximity communicator 110 may include a nearfield inductive driver circuit, a signal generator for producing audibletones, a motion signal generator for driving a body thump device, afield producing circuit for driving an electromagnet, and the like thatare responsive to the data commands. The proximity communicationcircuitry 310 may include near field telemetry or may omit suchtelemetry for examples where information is exchanged in other mannersor exclusively via a far field communication.

The controller 102 may include additional communication capabilitiesthat may be provided by far field communication circuitry 210 or byadditional communication circuitry. For instance, the controller 102 mayinclude Wi-Fi connectivity, public switched telephone networkconnectivity, and so forth to allow for remote communication,particularly where the controller 102 is a patient controlled device.

The memory 204 may be used to store information in use by the processor202. For instance, the memory 204 may store therapy parameters that areinput by a clinician or patient that are to be loaded into the IMD 104.The memory 204 may also store programming that is used by the processor202 to control an IMD selection procedure of the controller 102, tocontrol a recharge device selection procedure of the controller 102which is discussed below, and to control the delivery of the rechargeenergy by the recharge device 111 such as based on feedback receivedfrom the IMD 104 during the recharge process. The memory 204 may be ofvarious types, such as volatile, non-volatile, or a combination of thetwo.

The storage device 206 may be used to store information for a long termand may be of various types such as non-volatile so that the informationis retained when the controller 102 is powered off. The storage device206 may also store programming for the processor 202 that is implementedto control the IMD selection procedure, the recharge device selectionprocedure, and the delivery of recharge energy. Examples of the storagedevice 206 include electronic, magnetic, and optical drives. The storagedevice 206 and the memory 204 are both examples of computer readablemedia that may store information in the form of computer programming,data structures, and the like.

The processor 202 performs logical operations to provide a sequence offar field communications and may also provide a sequence of proximitycommunications for embodiments where the controller 102 may communicatedirectly with the IMD 104. The logical operations may allow thecontroller 102 to select the proper recharge device 111 at any giventime for a recharge session, and to control delivery of recharge energyduring the recharge session. Examples of such operations are discussedbelow in relation to FIG. 6. The processor 202 may be of various forms.For instance, the processor 202 may be a general-purpose programmableprocessor that executes software that is stored on the storage device206 or elsewhere. Other examples include a dedicated purpose hardwarecircuit or hard-wired digital logic. The processor 202 may be multipleseparate components or processors, dedicated hardware/state machine, andthe like. The processor 202 may communicate with the various othercomponents through one or more data buses.

FIG. 3 shows components of one example of the IMD 104 to be recharged.The IMD 104 includes a processor 302 and a memory 304. The IMD 104 alsoincludes medical circuitry 306 that performs a medical task such asstimulation, drug delivery, monitoring, and the like. The IMD 104 mayalso include far field communication circuitry 308 used to establish thefar field communication session with the controller 102 and/or rechargedevice 111. The far field communication circuitry 308 may drive a signalpropagation tool such as an integral RF antenna.

In addition to the far field communication circuitry 308, the IMD 104may also include proximity communication circuitry 310. The proximitycommunication circuitry 310 may be of various forms where for a givensystem, the type of proximity communication circuitry 310 matches thetype of proximity communicator 110 that the recharge device 111includes. Accordingly, the proximity communication circuitry 310 may bea near field inductive receiver, a microphone for receiving audibletones, an accelerometer or other vibration detection device, a fieldoperable switch such as a magnetic reed switch, and the like. Theproximity communication circuitry 310 may include near field telemetryor may omit such telemetry for examples where information is exchangedin other manners or exclusively via a far field communication.

The IMD 104 also includes a rechargeable battery 314 and a rechargecircuit 312 coupled to the battery 314. The recharge circuit 312 mayinclude a coil that inductively couples to the coil of the rechargecircuit 214 of the recharge device 111. The recharge circuit 312 mayutilize a dedicated coil or may utilize a coil that is also used by theproximity communication circuit 310. The recharge circuit 312 mayinclude rectification, filtering, voltage/current limiting, and the likeso as to provide an appropriate form of recharge power to the battery314.

The memory 304 may be used to store information in use by the processor302 such as programming and data values. The memory 304 may storeadditional information including therapy parameters that are used tocontrol the medical circuitry 306 as well as recharge parameters thatare used to control the recharge circuitry 312. The memory 304 may be ofvarious types such as volatile, non-volatile, or a combination of thetwo. The memory 304 is also an example of computer readable media thatmay store information in the form of computer programming, datastructures, and the like.

The processor 302 performs logical operations to provide a sequence offar field and proximity communications, and to control delivery ofreceived recharge energy to the battery 314. An example of these logicaloperations is discussed in more detail below with reference to FIG. 7.The processor 302 may be of various forms like those discussed above forthe processor 202 of the external device 102 and as discussed above maybe multiple separate components or processors, dedicated hardware/statemachine, and the like. The processor 302 may communicate with thevarious other components through one or more data buses.

FIG. 4 shows components of one embodiment of the recharge device 111 a.This embodiment 111 a may rely on the controller 102 to utilizeproximity communications with the IMD 104 to confirm that the far fieldcommunications of either the controller 102 or the recharge device 111 aare being exchanged with the correct IMD 104. Additionally oralternatively, this embodiment 111 a may rely on the controller 102 tocommunicate directly with the IMD 104 via far field communications suchthat the recharge device 111 communicates via far field communicationswith the controller 102.

The recharge device 111 a of FIG. 4 may include a processor 402 and amemory 404. The recharge device 111 a may also includes far fieldcommunication circuitry 406 used to establish the far fieldcommunication session with the controller 102 and/or the IMD 104. Thefar field communication circuitry 406 may drive a signal propagationtool such as an integral RF antenna.

The recharge device 111 also includes a battery 409 that is eitherrechargeable or replaceable and a recharge circuit 408 coupled to thebattery 409. The recharge circuit 408 may include a coil thatinductively couples to the coil of the recharge circuit 312 of the IMD104. The recharge circuit 408 generates recharge waveforms toinductively transfer energy to the IMD 104. The recharge circuit 408,for example, may include a coil that is driven by a waveform generatorthat receives energy from the battery 409. The recharge circuit 408 mayinclude filtering, voltage/current limiting, and the like so as to emitan appropriate form of recharge power to the IMD 104. The rechargecircuit 408 may drive the proximity communicator 109 which in thisembodiment is being used solely for the transfer of recharge energy tothe IMD 104. While the proximity communicator 109 has been shown inFIGS. 1 and 4 as being tethered to the recharge device 111, theproximity communicator 109 may be a component housed within the rechargedevice 111. Furthermore, in some embodiments the recharge device 111 maybe entirely self-contained such that the recharge device 111 can be wornby the patient while providing the transfer of recharge energy.

This embodiment 111 a may also include other features such as anaccelerometer 410. The accelerometer 410 may be included so that asignal may be generated that is representative of movement of therecharge device 111 a. As discussed below, this signal representative ofmovement may be communicated to the controller 102 to allow thecontroller to determine whether a particular recharge device 111 a is inthe closest proximity to the IMD 104 and is therefore the mostappropriate choice for providing recharge energy to the IMD 104. In thesimplest forms of the recharge device 111 a, this accelerometer isomitted in favor of other techniques that the controller 102 may use todetermine that the recharge device 111 a should begin providing rechargeenergy.

As an example where the accelerometer 410 may be used, the recharger 111a may not be attached to the patient but may be in a location that theIMD 104 would have proximal contact with the recharger 111 a sometimeduring the day, such as at a chair or bed. The movement detected by theaccelerometer 410 is an indication to the recharger 111 a that the IMD104 may be close to the recharger 111 a, and the recharger 111 a canexit a low power state and attempt to communicate with the IMD 104and/or controller 102. If the controller 102 is present, the recharger111 a may then attempt to recharge the IMD 104 under the direction ofthe controller 102.

The memory 404 may be used to store information in use by the processor402 such as programming and data values. The memory 404 may storeadditional information including recharge parameters that are used tocontrol the recharge circuitry 408. The memory 404 may be of varioustypes such as volatile, non-volatile, or a combination of the two. Thememory 404 is also an example of computer readable media that may storeinformation in the form of computer programming, data structures, andthe like.

The processor 402 performs logical operations to provide a sequence offar field communications and to control delivery of recharge energy bythe recharge circuit 408. An example of these logical operations isdiscussed in more detail below with reference to FIG. 6. The processor402 may be of various forms like those discussed above for the processor202 of the controller 102 and as discussed above may be multipleseparate components or processors, dedicated hardware/state machine, andthe like. The processor 402 may communicate with the various othercomponents through one or more data buses.

FIG. 5 shows components of another embodiment of the recharge device 111b. This embodiment 111 b may utilize proximity communications with theIMD 104 to confirm that the far field communications of either thecontroller 102 or the recharge device 111 b are being exchanged with thecorrect IMD 104. Additionally or alternatively, this embodiment 111 bmay utilize either far field communications or proximity communicationsto obtain recharge status information from the IMD 104.

The recharge device 111 b of FIG. 5 may include a processor 502 and amemory 504. The recharge device 111 b may also includes far fieldcommunication circuitry 506 used to establish the far fieldcommunication session with the controller 102 and/or the IMD 104. Thefar field communication circuitry 506 may drive a signal propagationtool such as an integral RF antenna.

The recharge device 111 b also includes a battery 509 that is eitherrechargeable or replaceable and a recharge circuit 508 coupled to thebattery 509. The recharge circuit 508 may include a coil thatinductively couples to the coil of the recharge circuit 312 of the IMD104. The recharge circuit 508 generates recharge waveforms toinductively transfer energy to the IMD 104. The recharge circuit 508,for example, may include a coil that is driven by a waveform generatorthat receives energy from the battery 509. The recharge circuit 508 mayinclude filtering, voltage/current limiting, and the like so as to emitan appropriate form of recharge power to the IMD 104. The rechargecircuit 508 may drive the proximity communicator 109 to provide thetransfer of recharge energy to the IMD 104.

In addition to the far field communication circuitry 506, the rechargedevice 111 b may also include proximity communicator circuitry 510 thatdrives the proximity communicator 109 to provide proximitycommunications with the IMD 104. As discussed above, these proximitycommunications may be used to ensure that the far field communicationsare being exchanged with the correct IMD 104 and to create a bond withthe IMD 104. The proximity communicator circuitry 510 may be of variousforms where for a given system, the type of proximity communicatorcircuitry 510 matches the type of proximity communication circuitry 310that the IMD 104 includes. Accordingly, the proximity communicatorcircuitry 510 may be a near field inductive transmitter, a speaker forproducing audible tones, a magnet, and the like.

This embodiment 111 b may also include other features such as anaccelerometer 512. The accelerometer 512 may be included so that asignal may be generated that is representative of movement of therecharge device 111 b. As discussed below, this signal representative ofmovement may be communicated to the controller 102 to allow thecontroller to determine whether a particular recharge device 111 b is inthe closest proximity to the IMD 104 and is therefore the mostappropriate choice for providing recharge energy to the IMD 104.

The memory 504 may be used to store information in use by the processor502 such as programming and data values. The memory 504 may storeadditional information including recharge parameters that are used tocontrol the recharge circuitry 508. The memory 504 may be of varioustypes such as volatile, non-volatile, or a combination of the two. Thememory 504 is also an example of computer readable media that may storeinformation in the form of computer programming, data structures, andthe like.

The processor 502 performs logical operations to provide a sequence offar field communications, a sequence of proximity communications, and tocontrol delivery of recharge energy by the recharge circuit 508. Anexample of these logical operations is discussed in more detail belowwith reference to FIGS. 6-7B. The processor 502 may be of various formslike those discussed above for the processor 202 of the controller 102and as discussed above may be multiple separate components orprocessors, dedicated hardware/state machine, and the like. Theprocessor 502 may communicate with the various other components throughone or more data buses.

FIG. 6 shows a set of logical operations that may be performed by thecontroller 102 in relation to one or more recharge devices 111 withinfar field communication range, or in some cases near field communicationrange of the controller 102 and the IMD 104 to be recharged to establisha recharge session. In this example, the controller 102 maintainswireless communications such as far field or near field communicationswith both the recharge device 111 and the IMD 104.

Initially in this example, the controller 102 discovers the presence ofand IMDs including the IMD 104 and detects whether the IMD 104 beingcommunicated with is the intended IMD to be recharged and/or has alreadybeen bonded to the controller 102 at a query operation 602. If the IMDbeing communicated with via the wireless communications is not alreadybonded as it does not have a communication key already shared with it bythe controller 102, the controller 102 may then initiate proximalcommunications at communication operation 604. Here the controller 102can detect whether the IMD 104 which is receiving the proximalcommunications is also receiving the wireless communications to confirmthat the wireless communications are with the correct IMD 104,particularly where the wireless communications are far fieldcommunications. Once that has been confirmed, the controller 102 maythen share the communication key with the IMD 104 such as over theproximal communication link so as to create the bond with the IMD 104.

In some embodiments, the controller 102 sends an instruction to the IMD104 to enter a recharge mode at an instruction operation 606 so that theIMD 104 may begin receiving recharge energy and allowing it to passthrough any rectification, filters, regulators and the like andultimately to the battery 314. In some embodiments, the IMD 104 may beconfigured to always receive transferred energy to send to the battery314 such that the instruction operation 606 is not implemented.Furthermore, for embodiments where the controller 102 is already bondedto the IMD 104, the logical operations may start at the instructionoperation 606 or may start at a subsequent operation such as where theIMD 104 is always configured to receive the transfer of energy.

The subsequent operation for the controller 102 is to instruct anappropriate recharge device 111 over a wireless communication which maybe a far field communication for example to begin transferring rechargeenergy at an instruction operation 608. For embodiments where there is asingle recharge device 111 paired with the controller 102, then thecontroller 102 communicates with that recharge device 111. For instance,the patient or other user of the controller 102 may be aware that thepatient, and hence the IMD 104, is in close proximity to the singlerecharge device 111 and may select an option to begin recharging and thecontroller 102 then sends the instruction. As another example, thecontroller 102 may continually query for the presence of the singlerecharge device 111 such as by using a communication key shared by boththe controller 102 and the recharge device 111. Upon receiving aresponse from the recharge device 111, the controller 102 may thencommunicate with the single recharge device 111 to determine whetherthat single recharge device 111 is in proximity to the IMD 104 in orderto determine whether to send the instruction to begin recharging.

FIGS. 8 and 9, discussed in more detail below, show logical operationsallowing the controller 102 to make a determination about whether aparticular recharge device 111 is appropriate for recharging and may usethose operations to determine whether a single recharge device 111 isappropriately in proximity to begin recharging. Furthermore, thecontroller 102 may poll for the presence of multiple recharge devices111 that may be present and may then utilize the operations of FIGS. 8and/or 9 to determine which recharge device 111 of the plurality thatare present is the most appropriate to begin providing recharge energyto the IMD 104 at any given time.

As an alternative to the controller 102 communicating directly with therecharge device 111 at the instruction operation 108, the controller 102may instead communicate directly with the IMD 104 to communicate therecharge instruction. The IMD 104 may have an established communicationlink with the recharge device 111 or may create one. This communicationlink may be via proximal telemetry or may be via a far fieldcommunication session. In either case, the IMD 104 may then send therecharge instruction to the recharge device 111.

As an alternative to instructing the recharge device 111 to beginrecharging, the recharge device 111 may be configured to automaticallybegin the recharging process upon detecting that an IMD 104 is inproximity, such as by periodically determining activating the rechargecoil and determining whether a load is present, such as is discussedbelow with reference to FIG. 8. The controller 102 may then be used toturn the recharge process on or off in response to user input. Thus, thecontroller 102 may establish the communication link with the rechargedevice 111 at the communication operation for purposes of deactivatingthe transfer of recharge energy either immediately or at some point inthe future as may be selected by the user.

Once the instruction to begin recharging has begun, the controller 102may then detect whether it is time to check the recharging status of theIMD 104 at a query operation 610. Once it is time to check therecharging status of the IMD 104, the controller 102 then obtainsrecharge information from the IMD 104 by sending a request for theinformation over the wireless communication link at a communicationoperation 612. In some embodiments, this may call for a wake-upprocedure where the IMD 104 may put the wireless communications,particularly far field communications, in a sleep mode between queriesfor the recharge status.

Upon obtaining the recharge status information, the controller 102 maydetect whether the battery 314 is fully charged such as based onrecharge status information including available battery voltage, batteryimpedance, amount of current passing to the battery 314 and so forth ata query operation 614. If the battery 314 is not fully charged, then thecontroller 102 then allows recharging to continue but provides aninstruction to adjust the recharging if such an adjustment is needed atan adjustment operation 615. For instance, the controller 102 mayrequest that the amount of energy be increased such as to shorten thetime to complete the recharge or be decreased to prevent a harmfulcondition. The controller 102 again detects whether the time has come tocheck for recharge status at the query operation 610. If the battery 314is fully charged, then the controller 102 then instructs the rechargedevice 111 to stop the transfer of recharge energy at an instructionoperation 616 and instructs the IMD 104 to exit the recharge mode, forembodiments where such is appropriate, at an instruction operation 618.This instruction to the recharge device 111 to stop the transfer ofrecharge energy may be provided directly to the recharge device 111where a direct communication link is established or may be provided tothe IMD 104 which then provides the instruction to the recharge device111 over an established communication link.

FIG. 7A shows the operations of the controller 102 where the rechargedevice 111 establishes a wireless communication link, either via farfield or near field, with the IMD 104 that is intended to be recharged.Initially, the controller 102 instructs the appropriate recharge device111 to begin transferring recharge energy at an instruction operation702. As discussed above, where there is a single recharge device 111paired to the controller 102, then the controller 102 sends thisinstruction to the recharge device 111. As also discussed above, thisinstruction may be sent on the basis of a user requesting recharge tobegin in one example or may be sent on the basis of the controller 102determining from wireless communications with the recharge device 111that the recharge device is in proper proximity to the IMD 104 forpurposes of recharging.

This instruction triggers the recharge device 111 to establishcommunications with the IMD 104 and to instruct the IMD 104 to enter therecharge mode if appropriate. These communications may be via a farfield communication link where both the recharge device 111 and the IMD104 are equipped to do so. These communications may alternatively be viaa near field communication link which may use the same telemetry head109 that is also being used to transfer the recharge energy.

Once recharging has begun, the controller 102 may then detect whether itis time to check the recharging status of the IMD 104 at a queryoperation 704. Once it is time to check the recharging status of the IMD104, the controller 102 then obtains recharge information from the IMD104 by sending a request for the information over the wirelesscommunication link with the recharge device 111 at a communicationoperation 706. This triggers the recharge device 111 to request thisinformation from the IMD 104 including waking up the IMD 104 from asleep mode if necessary, and then to report that information to thecontroller 102 upon receiving it from the IMD 104. In some embodiments,this may call for a wake-up procedure where the IMD 104 may put thewireless communications, particularly far field communications, in asleep mode between queries for the recharge status.

Upon obtaining the recharge status information, the controller 102 maydetect whether the battery 314 is fully charged such as based onrecharge status information including available battery voltage, batteryimpedance, amount of current passing to the battery 314 and so forth ata query operation 708. If the battery 314 is not fully charged, then thecontroller 102 then allows recharging to continue and again detectswhether the time has come to check for recharge status at the queryoperation 704. If the battery 314 is fully charged, then the controller102 then instructs the recharge device 111 to stop the transfer ofrecharge information at an instruction operation 710. This triggers therecharge device 111 to terminate the communication session with the IMD104 and to instruct the IMD 104 to exit the recharge mode ifappropriate.

FIG. 7B shows logical operations of the recharge device 111 that isworking in conjunction with the controller 102 performing the logicaloperations of FIG. 7A. In such a case, the controller 102 may notcommunicate directly with the IMD 104 but may rely on the recharger 111to communicate with the IMD 104 and then relay information between thecontroller 102 and the IMD 104.

Alternatively, these operations of FIG. 7B may work in conjunction withthe logical operations of FIG. 6 such as where the controller 102communicates with both the IMD 104 and the recharger 111 via theoperations of FIG. 6, while the recharger 111 communicates with thecontroller 102 and the IMD 104 via the operations of FIG. 7B. In such anexample, the recharger 111 may communicate with the IMD 104 to monitorthe status of the recharge coupling between the two which the recharger111 may then report this recharge status information to the controller102 and then receive instructions to adjust output power and the like.Meanwhile the controller 102 may communicate directly with the IMD 104to monitor recharge status information of the IMD 104 such as thebattery status in order to ultimately control the recharge process andto also store relevant data about the recharge process within the IMD104 which may be later obtained and reviewed by a clinician.

In FIG. 7B, the recharge device 111 may continually listen for andeventually receive the instruction to begin transferring recharge energyat the instruction operation 712. For embodiments where thecommunication link from the recharge device 111 to the IMD 104 is a farfield link, the recharge device 111 may then proceed to discover IMDsand then determine whether the IMD involved in the far fieldcommunications is bonded to the recharge device 111 and/or whether thatIMD is the intended IMD 104 at a query operation 714.

If the IMD being communicated with via the far field communications isnot already bonded as it does not have a communication key alreadyshared with it by the recharge device 111, the recharge device 111 maythen initiate proximal communications at communication operation 716.Here the recharge device 111 can detect whether the IMD 104 which isreceiving the proximal communications is also receiving the far fieldcommunications to confirm that the far field communications are with thecorrect IMD 104. Once that has been confirmed, the recharge device 111may then share the communication key with the IMD 104 such as over theproximal communication link so as to create the bond with the IMD 104.

In some embodiments, the recharge device 111 sends an instruction to theIMD 104 to enter a recharge mode at an instruction operation 718 so thatthe IMD 104 may begin receiving recharge energy and allowing it to passthrough any rectification, filters, regulators and the like andultimately to the battery 314. In some embodiments, the IMD 104 may beconfigured to always receive transferred energy to send to the battery314 such that the instruction operation 718 is not implemented.Furthermore, for embodiments where the recharge device 111 is alreadybonded to the IMD 104 or where near field communications are used, thelogical operations may start at the instruction operation 718 or maystart at a subsequent operation such as where the IMD 104 is alwaysconfigured to receive the transfer of energy.

The subsequent operation for the recharge device 111 is to begintransferring recharge energy at a recharge operation 720. Once therecharging has begun, the recharge device 111 may then detect whether itis time to check the recharging status of the IMD 104 at a queryoperation 722. Once it is time to check the recharging status of the IMD104, the recharge device 111 then obtains recharge information from theIMD 104 by sending a request for the information over the wirelesscommunication link such as a far field communication link at acommunication operation 724. In some embodiments, this may call for awake-up procedure where the IMD 104 may put the wireless communicationsin a sleep mode between queries for the recharge status.

Upon obtaining the recharge status information, the recharge device 111then reports that status information via the wireless communication linkwith the controller 102 at a communication operation 726. The controller102 may then detect whether the battery 314 is fully charged such asbased on recharge status information including available batteryvoltage, battery impedance, amount of current passing to the battery 314and so forth. At the query operation 728, the recharge device 111detects whether the controller 102 has responded with an instruction tostop providing the recharge energy. If the battery 314 is not fullycharged, then the controller 102 will not send the instruction to stopand the recharge device 111 then allows recharging to continue and againdetects whether the time has come to check for recharge status at thequery operation 722. If the battery 314 is fully charged, then thecontroller 102 then instructs the recharge device 111 to stop thetransfer of recharge information and the recharge device 111 stops thetransfer of energy and instructs the IMD 104 to exit the recharge mode,for embodiments where such is appropriate, at a recharge operation 730.

FIG. 8 shows logical operations of the controller 102 where multiplerecharge devices 111 are available and a selection of the mostappropriate recharge device is desired and/or where a single rechargedevice 111 is available and automatically initiating recharge isdesired. Initially, the controller 102 discovers the single rechargedevice 111 or multiple recharge devices 111 that are available over awireless communication link at a discovery operation 802. The controller102 receives responses to the discovery request and may select aresponse to establish a wireless session with the responding device ormay establish a wireless session with each responding device such aswhere the wireless communication link is a far field link.

The controller 102 then instructs a recharge device 111 of one of thesessions to provide recharge energy at an instruction operation 804. Thecontroller 102 then instructs the IMD 104 to enter the recharge mode,after having established wireless communications with the correct IMD104 at an instruction operation 806. The controller 102 obtains therecharge status from the IMD 104 at a status operation 808. Thecontroller 102 then detects whether the IMD 104 is receiving rechargeenergy at a query operation 810. If the IMD 104 is not receivingrecharge energy, then presumably the recharge device 111 that has beeninstructed to provide the recharge energy is not the most appropriateone as it is not in proximity to the IMD 104.

The controller 102 then instructs the current recharge device 111 tostop transferring energy at an instruction operation 812 and switches tothe communication session of the next recharge device 111 that has beendiscovered at operation 816. In the case of the single recharge device111 that has been discovered, the controller merely delays for a presetperiod of time at operation 816. The controller 102 then instructs thenext recharge device 111, or again instructs the single recharge device111, to begin transferring recharge energy at instruction operation 808,and the operational flow proceeds as described above.

Upon the controller 102 detecting that energy is being received by theIMD 104 at the query operation 810, then controller 102 then allows therecharging to continue until the recharge status is a fully chargedbattery 314 at a recharge operation 814. The recharge operation 814 maycorrespond to the operations 610-618 of FIG. 6.

FIG. 9 shows another example of logical operations of the controller 102where multiple recharge devices 111 are available and a selection of themost appropriate recharge device is desired and/or where a singlerecharge device 111 is available and automatically initiating rechargeis desired. Initially, the controller 102 discovers the single rechargedevice 111 or multiple recharge devices 111 that are available over awireless communication link at a discovery operation 902. The controller102 receives responses to the discovery request and may select aresponse to establish a wireless session with the responding device ormay establish a wireless session with each responding device where thewireless sessions are far field sessions.

The controller 102 then queries via a wireless communication a rechargedevice 111 of one of the sessions to provide status regarding motion ofthe recharge device 111 and receives that information at a requestoperation 904. The recharge device 111 collects informationrepresentative of motion from the accelerometer, 410, 512. Thecontroller 102 then detects whether the current recharge device 111 hasmotion representative of being positioned in proper proximity to thepatient at a query operation 906. Presumably if the recharge device 111is experiencing motion over a preset threshold indicative of proximityto the patient, then the recharge device 111 is appropriately positionedfor delivering recharge energy to the IMD 104 of the patient.

Where the motion status of the current recharge device 111 does notindicate proximity to the patient, then controller 102 switches to thecommunication session of the next recharge device 111 that has beendiscovered at operation 908. In the case of the single recharge device111 that has been discovered, the controller merely delays for a presetperiod of time at operation 908. The controller 102 then queries thenext recharge device 111, or again queries the single recharge device111, to report the motion status at the request operation 904, and theoperational flow proceeds as described above.

Upon the controller 102 detecting that the current recharge device 111is experiencing motion indicative of proximity to the patient, then thecontroller 102 instructs that the transfer of energy begins and thatrecharging mode be entered where appropriate until the recharge iscomplete at a recharge operation 910. The recharge operation 910 maycorrespond to the operations 606-618 of FIG. 6.

In addition to or as an alternative to checking for motion, thecontroller 102 may also query the recharge device 111 to determine ifthe recharge device 111 is experiencing a load upon attempting totransfer recharge energy at the query operation 906. In some cases, aload may indicate that the recharge device 111 is inductively coupled tothe IMD 104 and is appropriate for providing recharge energy. However, aload may be the result of an inductive coupling to another object.Similarly, motion of the recharge device 111 may be the result ofsomething other than proximity to the patient. Thus, the presence of aload and the presence of motion of the recharge device 111 that istypical for being in proximity to the patient may provide a moreaccurate conclusion that the recharge device 111 is in proximity to thepatient.

Some embodiments of the IMD 104 may employ both the operations of FIG. 8and those of FIG. 9 to further confirm that a particular recharge device111 is appropriate. For instance, the controller 102 may first determinewhether the IMD 104 is receiving recharge energy as in FIG. 8, such aswhere the controller 102 instructs all recharge devices 111 to begintransferring energy at the same time. If the IMD 104 is receivingrecharge energy, then the controller 102 may then detect which rechargedevice 111 is providing it by querying each recharge device 111 formotion indicative of proximity to the patient and/or for a loadindicative of an inductive coupling to the IMD 104.

In relation to FIGS. 8 and 9, the recharge operations 814 and 910 mayinclude repeating the detection of whether the IMD 104 is continuing toreceive recharge energy as in FIG. 8 or whether the motion of therecharge device 111 continues to meet the threshold regarding proximityto the patient as in FIG. 9. Where the controller 102 detects that therecharge device 111 that is currently providing recharge energy is nolonger the appropriate recharge device 111 due to a lack of energy beingtransferred or a lack of motion indicative of proximity to the patient,then the controller 102 may communicate with the current recharge device111 to stop the transfer of energy even though the battery 314 was notfully charged.

Furthermore, the controller 102 may immediately begin communicating withother recharge devices 111 that may have been discovered to test eachone for the proper transfer of energy to the IMD 104 and/or for the anadequate level of motion indicative of proximity to the IMD 104. In thismanner, the patient with the IMD 104 may move about during the rechargeprocess such that the controller 102 may allow recharging to continue byactivating and deactivating recharge devices 111 that the patient mayencounter. For example, the patient may have recharge devices 111located at several locations within the home of the patient, and thepatient may move from area to area within the home while rechargingcontinues by utilizing the most appropriate recharge device 111 withinthe home at any given time.

A specific example of the system including the controller 102, rechargedevice 111, and IMD 104 is now described. The description of thisspecific example is for illustrative purposes and is not intended to belimiting with respect to any aspect of the recharging process and theinteraction between the controller 102, the recharger 111, and the IMD104.

The controller 102 of this example employs a Bluetooth transceiver aswell as a MICS transceiver. The controller 102 also includes a touchscreen for providing a user interface display. The controller 102includes button controls that receive selections by the user.

The recharger 111 of this example is a single unit having a disk shapethat encloses the recharge coil. The recharger 111 has Bluetoothcommunication and electronics to control recharge levels to the rechargecoil, and the recharger 111 communicates only with the controller 102.The recharger 111 as a port that plugs into a docking station, which iswhere the recharger is placed by the user when not recharging the IMD104. This docking station recharges the batteries within the recharger111 and keeps the battery charged until a recharge session occurs.

When on the docking station, the recharger 111 does not start a rechargesession but provides information via Bluetooth to the controller 111about the status of the on-board batteries. The recharger 111 may bemade less expensive and more rugged by omitting a user interface. Thecontroller 102 can provide all information to the user regarding therecharge process. To bond the controller 102 to a recharger 111, therecharger 111 is placed in the docking station, and a button on thedocking station is pressed to initiate Bluetooth discovery between thecontroller 104 and all the rechargers 111 in the docking station wherethere may be more than one.

Whenever the recharger 111 is out of the docking station, the recharger111 will actively look for an IMD 104 to recharge. The recharger 111 mayuse loading of the recharge coil to determine if a metal object such asan IMD 104 is close. If close enough so that the controller 102 is incommunication range, the recharger 111 tells the controller 102 that therecharger 111 has found something to recharge and that the recharger 111is ready to begin recharging. The controller 102 attempts to communicatewith the IMD 104 and if successful, the controller 102 initiates therecharge process on the recharger 111 and monitors the current enteringinto the IMD 104. The controller 102 may then provide feedback to theuser regarding how well coupled the recharger 111 is to the IMD 104. Ifthe controller 102 cannot communicate with the IMD 104, the controller102 tells the user that the IMD 104 is not found and asks if the userwants to recharge anyway. This covers the situation where the IMD 104 isfully depleted and cannot communicate. If the user agrees, thecontroller 102 starts the recharge session and attempts to gaincommunication with the IMD 104 while recharge is occurring. Thecontroller 102 ends the recharge session and notifies the user if, afterseveral minutes, the IMD 104 still has not started to communicate.

During the recharge session, the recharger 111 provides antennatemperature information and recharger settings and measurements to thecontroller 104. Meanwhile, the IMD 104 stores information about therecharge diagnostics measured by the IMD 104, such as recharge current,length of recharge, and battery voltage. The controller 102 retrievesall the necessary information about recharging from the IMD 104 via theMICS band communications and from the recharger 111 via the Bluetooth®connection to allow the controller 102 to adjust the recharge via areturn Bluetooth® communication to the recharger 111. In this manner,the recharger 111 has no need to communicate directly with the IMD 104,which simplifies the design of the recharger 111.

The controller 102 controls the settings of the recharger 111 to managethe energy output of the recharger 111 based on recharge data. The goalof the controller 102 is to limit the heat generated from the rechargingsession and to inform the user about how well the recharge session isperforming.

While embodiments have been particularly shown and described, it will beunderstood by those skilled in the art that various other changes in theform and details may be made therein without departing from the spiritand scope of the invention.

What is claimed is:
 1. A method of recharging an implantable medicaldevice, comprising: sensing by a controller device the presence of afirst recharge device relative to the controller device where the firstrecharge device is separately enclosed from the controller device; andin response to sensing the presence of the first recharge devicerelative to the controller device, automatically without user inputinstructing by the controller device the first recharge device to beginthe transfer of recharge energy from the first recharge device to theimplantable medical device wherein the implantable medical device isseparately enclosed from the controller device and the first rechargedevice.
 2. The method of claim 1, further comprising: prior toinstructing the first recharge device to begin the transfer of rechargeenergy, sensing the presence of a second recharge device; detectingwhich of the first recharge device and second recharge device is incloser proximity to the implantable medical device; and when detectingthat the first recharge device is in closer proximity to the implantablemedical device, then communicating with the first recharge device tocontinue the transfer of energy to the implantable medical device. 3.The method of claim 2, further comprising: after instructing the firstrecharge device to begin the transfer of energy from the first rechargedevice to the implantable medical device, detecting that the secondrecharge device is in closer proximity to the implantable medicaldevice; and after detecting that the second recharge device is in closerproximity to the implantable medical device, then communicating with thesecond recharge device to continue the transfer of recharge energy tothe implantable medical device.
 4. The method of claim 2, whereindetecting which of the first recharge device and second recharge deviceis in closer proximity comprises detecting whether the first rechargedevice and the second recharge device have recharge loads whenoutputting recharge energy.
 5. The method of claim 4, wherein detectingwhich of the first recharge device and second recharge device is incloser proximity comprises when the first recharge device is outputtingrecharge energy and the second recharge device is not outputtingrecharge energy, detecting whether the implantable medical device isreceiving recharge energy.
 6. The method of claim 2, wherein detectingwhich of the first recharge device and the second recharge device is incloser proximity comprises detecting whether the first recharge deviceis being moved.
 7. The method of claim 6, further comprising activatinga wireless communication circuit of the first recharge device upondetection of the first recharge device being moved and subsequentlysending a response from the first recharge device upon receiving aninstruction from the first controller via the wireless communications.8. The method of claim 7, wherein the wireless communications are farfield communications.
 9. The method of claim 1, wherein sensing thepresence of the first recharge device comprises polling for the firstrecharge device using a communication key stored by both the firstcontroller and the first recharge device.
 10. A medical system,comprising: an implantable medical device; a first recharge device thatis distinct from the implantable medical device; and a controller thatis separately enclosed from the implantable medical device and that isseparately enclosed from the first recharge device, wherein thecontroller senses the presence of the first recharge device relative tothe controller and in response to sensing the presence of the firstrecharge device relative to the controller, automatically without userinput instructs the first recharge device to begin the transfer ofrecharge energy from the first recharge device to the implantablemedical device.
 11. The medical system of claim 10, wherein prior toinstructing the first recharge device to begin the transfer of rechargeenergy, the controller senses the presence of a second recharge device,detects which of the first recharge device and second recharge device isin closer proximity to the implantable medical device, and upondetecting that the first recharge device is in closer proximity to theimplantable medical device, instructs the first recharge device totransfer recharge energy to the implantable medical device.
 12. Themedical system of claim 11, wherein after instructing the first rechargedevice to begin the transfer of energy from the first recharge device tothe implantable medical device, the controller detects that the secondrecharge device is in closer proximity to the implantable medicaldevice, and after detecting that the second recharge device is in closerproximity to the implantable medical device, the controller communicateswith the second recharge device to transfer recharge energy to theimplantable medical device.
 13. The medical system of claim 11, whereinthe controller detects which of the first recharge device and secondrecharge device is in closer proximity by detecting whether the firstrecharge device and the second recharge device have recharge loads whenoutputting recharge energy.
 14. The medical system of claim 13, whereinthe controller detects which of the first recharge device and secondrecharge device is in closer proximity by detecting whether theimplantable medical device is receiving recharge energy when the firstrecharge device is outputting recharge energy and the second rechargedevice is not outputting recharge energy.
 15. The medical system ofclaim 11, wherein the controller detects which of the first rechargedevice and the second recharge device is in closer proximity bydetecting whether the first recharge device is being moved.
 16. Themedical system of claim 15, wherein the controller sends a signal toactivate a wireless communication circuit of the first recharge deviceupon detecting that the first recharge device is being moved, andwherein the first recharge device subsequently sends a response uponreceiving an instruction from the controller via the wirelesscommunications.
 17. The medical system of claim 16, wherein the wirelesscommunications are far field communications.
 18. The medical system ofclaim 10, wherein the controller senses the presence of the firstrecharge device by polling for the first recharge device using acommunication key stored by both the first controller and the firstrecharge device.
 19. A method of recharging an implantable medicaldevice, comprising: sensing by a controller device the presence of afirst recharge device; in response to sensing the presence of the firstrecharge device, instructing by the controller device the first rechargedevice to begin the transfer of recharge energy from the first rechargedevice to the implantable medical device; prior to instructing the firstrecharge device to begin the transfer of recharge energy, sensing thepresence of a second recharge device; detecting which of the firstrecharge device and second recharge device is in closer proximity to theimplantable medical device; and when detecting that the first rechargedevice is in closer proximity to the implantable medical device, thencommunicating with the first recharge device to continue the transfer ofenergy to the implantable medical device.
 20. A medical system,comprising: an implantable medical device; a first recharge device; anda controller, wherein the controller senses the presence of the firstrecharge device and in response to sensing the presence of the firstrecharge device, instructs the first recharge device to begin thetransfer of recharge energy from the first recharge device to theimplantable medical device, wherein prior to instructing the firstrecharge device to begin the transfer of recharge energy, the controllersenses the presence of a second recharge device, detects which of thefirst recharge device and second recharge device is in closer proximityto the implantable medical device, and upon detecting that the firstrecharge device is in closer proximity to the implantable medicaldevice, instructs the first recharge device to transfer recharge energyto the implantable medical device.